Type 1 diabetes is a disorder in which the pancreas fails to produce…

The idea

Insulin is the hormone released by the pancreas when blood glucose rises after a meal. It travels in the blood and causes liver and muscle cells to take up glucose and store it as glycogen, lowering blood glucose. In Type 1 diabetes the pancreatic cells that make insulin are damaged, so too little insulin is secreted. Without enough insulin, glucose stays in the blood instead of entering cells, producing the high blood glucose that characterises the disorder. A useful method is to trace the pathway pancreas → insulin → target cells → glucose uptake, then remove insulin and predict the consequence.

What earns the marks

• Insulin is a hormone produced by the pancreas that lowers blood glucose concentration.
• In Type 1 diabetes the pancreas does not secrete sufficient insulin.
• The cause is a failure of the insulin-producing cells of the pancreas, not a failure of body cells to respond.
• Reduced insulin means less glucose is taken up by liver and muscle cells and less is stored as glycogen.
• As a result blood glucose concentration remains higher than normal after meals.
• Type 1 diabetes is a disorder of insulin production, so it is distinct from Type 2 diabetes.

Common mistakes and how to put them right

• Confusing Type 1 with Type 2 by writing that body cells no longer respond to insulin.

  Put it right: That describes Type 2, whereas Type 1 is a failure of insulin production.

• Stating that insulin is a digestive enzyme or that it is made in the liver.

  Put it right: Insulin is a hormone made by the pancreas and acts on target cells.

Exam tips

• Use the phrase insufficient insulin rather than no insulin, matching the specification wording.
• Name both the organ and the hormone in your answer: pancreas and insulin.
• If asked to explain consequences, continue the chain to high blood glucose rather than stopping at the pancreas.